Answer / vishnu948923

system calls are provided by the system and are executed in
the system kernel. They are entry points into the kernel and
are therefore NOT linked into your program. These are not
portable calls.
· Library calls include the ANSI C standard library and
are therefore portable. These functions are linked into your
program.
It is worth noting that, because system calls are part of
the O/S. The program has to make a context switch to the
kernel when they are called and because of this, they have a
high startup overhead. The upside is that the time executing
these routines is assigned to the OS and not the user program.

Answer / eng abedalmohdi almomani

system call can be called from either kernel space or user
space(in this case include switch to privilage mode) and
executed in kernel space while library called only from
user programm and may call systemcall to perform it is
function like "printf" that need "write" system call while
other not need kernel at all like sin(),cos().....

systemcall examples : write,read,close,mmap,open,.......
library examples: fopen,fclose,printf,scanf,fscanf,.....

#include<stdio.h> int f(int,int); int main() { printf("%d",f(20,1)); return 0; } int f(int n,int k) { if(n==0) return 0; else if(n%2)return f(n/2,2*k)+k; else return f(n/2,2*k)-k; } how this program is working and generating output as 9....?

1 Answers  

---

diff. between *p and **p

3 Answers  

---

write a program to count the no of repaeted words in a line?

1 Answers  

---

Which programming language is best for getting job 2020?

0 Answers  

---

Look at the Code: main() { int a[]={1,2,3},i; for(i=0;i<3;i++) { printf("%d",*a); a++; } } Which Statement is/are True w.r.t the above code? I.Executes Successfully & Prints the contents of the array II.Gives the Error:Lvalue Required III.The address of the array should not be changed IV.None of the Above. A)Only I B)Only II C)II & III D)IV

5 Answers   Accenture,

---

Explain what is gets() function?

0 Answers  

---

The differences between Windows XP and Windows Visa

8 Answers   HCL,

---

PLS U SENS ME INTERVIEW O. MY EMAIL ADD, SOFIYA.SINGH@GMAIL.COM

0 Answers  

---

How do I access command-line arguments?

2 Answers   Bosch, Wipro,

---

How many types of operator or there in c?

0 Answers  

---

what are non standard function in c

0 Answers  

---

write a program in 'c' to find the value of p[i+1]^n.p,i,n are arguments of a macro and n is a integer

1 Answers  

---